The present invention relates to a planning procedure for clearing mail sorting machine outputs concurrently with a mail sorting process.
Mail sorting machines are known which receive at the input a stream of randomly arranged mail items, and produce at the output a sequenced stream of mail items, i.e. arranged in a predetermined progressive order enabling sequential distribution by one or more mailmen assigned to a given route.
More specifically, known mail sorting machines normally comprise an input (also said induction) receiving a mail batch, i.e. a set of mail items for sorting; a number of outputs, which may be assigned respective containers into which respective groups of mail items are fed; and a sorting device interposed between the input and outputs of the machine and controlled by an electronic processing unit to direct each mail item to a respective output on the basis of a code, normally printed on the mail item, and a table relating the code to a given machine output.
The progressive order in which the mail items in each batch are arranged at the machine outputs may be defined, for example, by a sequence of adjacent delivery locations or destinations corresponding to building numbers or groups of building numbers along the delivery route of the mail items in the batch.
Each mailman responsible for delivering the mail items in the batch is assigned a specific respective group of machine outputs, from which, at the end of the sorting process, the mail items are withdrawn and handed over for delivery.
The sorting process performed by a mail sorting machine on a given mail batch typically comprises a number of consecutive sorting cycles whereby groups of mail items are fed repeatedly through the machine and directed to outputs associated with containers from which the mail items deposited in the previous sorting cycle have been removed.
By the end of the sorting cycles, the mail items coming off the machine are arranged in groups in a predetermined progressive order enabling sequential distribution by a mailman assigned to a subsection of a given route.
Mail sorting machines of the above type are normally capable of different mail processing modes.
In particular, the machine may perform in chronologically consecutive order all the sorting cycles of a sorting process relating to the same mail batch; may perform in chronologically consecutive order a number of same-sequence-position sorting cyclesxe2x80x94e.g. a number of second sorting cyclesxe2x80x94of sorting processes relating to different mail batches; or may perform a number of different-sequence-position sorting cycles of sorting processes relating to different mail batches.
A drawback common to all known sorting processes is the possibility of one or more outputs on the machine filling up in the course of a sorting cycle, in which case, the relative sorting process cannot be continued while the output is being cleared.
In particular, if other than occasional, fill-up of the outputs in the course of a sorting cycle other than the first severely impairs efficiency by inevitably requiring interruption of the current sorting cycle to clear the output, thus resulting in considerable downtime due not only to the interruption in the sorting cycle but also to the numerous precautions which must be taken as regards processing of the mail items before the sorting process can be re-started.
Nor is anything to be gained by overlapping the sorting and clearing operations when switching from one cycle to another involving the same set of outputs, in that, failing stoppage of the system or routing artifices, which can only be employed in very limited cases, the mail items not accommodated in the output being cleared would fall out of sequence, thus resulting in rejection and the need for additional processing to reestablish the correct sequence.
It is an object of the present invention to provide a planning procedure for clearing mail sorting machine outputs concurrently with a mail sorting process, designed to eliminate the aforementioned drawbacks.
According to the present invention, there is provided a planning procedure for clearing mail sorting machine outputs concurrently with a current sorting cycle of a mail sorting process comprising a first and at least a second logically consecutive sorting cycle; said current sorting cycle being performed by a mail sorting machine receiving a batch of mail items at the input and supplying said mail items, identified and separated according to given sorting rules, at outputs of the mail sorting machine; in one sorting cycle, the mail items being fed to the outputs of the mail sorting machine on the basis of a respective predetermined sorting criterion, and being fed in orderly manner back to the input of the mail sorting machine to perform a successive sorting cycle; each output of the mail sorting machine being assigned, at each sorting cycle, a number of respective delivery locations to which the mail items are to be delivered; the operating state of the outputs of the mail sorting machine in the current sorting cycle and in the logically preceding sorting cycle, and indicating the time intervals in which the outputs are available or unavailable for sorting mail items, being represented by a matrix in which each column represents the operating state of a respective output of the mail sorting machine in the current sorting cycle, and each row represents the operating state of a respective output of the mail sorting machine in the logically preceding sorting cycle; each box in the matrix being assigned a respective said delivery location; and the column and the row of each box representing the outputs of the mail sorting machine occupied, by the mail items bearing the delivery location assigned to said box, at the end of the current sorting cycle and the logically preceding sorting cycle respectively; said planning procedure being characterized by comprising the step of defining, in said matrix, non-addressable boxes to which delivery locations cannot be assigned, so that the current sorting cycle contains time intervals in which no mail items are fed into the outputs of the mail sorting machine corresponding to the columns containing said non-addressable boxes, and said outputs may therefore be cleared by a clearing resource during said time intervals.